Urethane hybrid agricultural vehicle track

ABSTRACT

Endless vehicle tracks including a body having an outer surface formed of an elastomeric material displaying a series of ground engaging profiles longitudinally spaced along the outer surface, and an inner surface formed a urethane reinforcement material. The inner surface generally displays a series of longitudinally spaced guide-drive lugs for retaining the track on the vehicle and/or driving the vehicle. In some aspects, the urethane reinforcement defines the inner surface of the body, and the urethane reinforcement may even be a continuous structure forming a base of the inner surface. In some cases, the urethane reinforcement defines wheel path regions of the body, and the urethane reinforcement may even form the guide-drive lugs. In some embodiments, the endless vehicle track further includes a fabric reinforcement layer disposed beneath or upon the outer surface of the upper face of the guide-drive lugs.

FIELD

The field to which the disclosure generally relates is vehicle tracks,and more particularly to vehicle tracks having guide-drive lugs andwheel path areas formed of urethane materials.

BACKGROUND

This section provides background information to facilitate a betterunderstanding of the various aspects of the disclosure. It should beunderstood that the statements in this section of this document are tobe read in this light, and not as admissions of prior art.

Positive guide-drive, endless rubber tracks such as those used onagricultural or industrial vehicles typically have an internal, centerrow of individual guide-drive lugs which engage guide-drive bars on aguide-drive wheel. The continued use and contact between the guide-drivebar and guide-drive lugs cause internal lug stresses and surface wear atthe points of contact. Additionally, the internal, center row of lugsare typically functioning not only to transmit power from theguide-drive wheel to the track, but also to retain the track on thevehicle. Contact between the vehicle undercarriage wheels and lateralend of the guide surfaces of the inner lugs frequently occurs as thevehicle maneuvers during normal service. This contact can cause wearingof the inner lugs, which can be severe, depending upon various vehicledesign features and application use. Driving and/or guiding forces onthe inner lugs, henceforth referred to also as guide-drive lugs, canlead to cracks and eventual chunking of the rubber surface, and possiblyto complete removal of the guide-drive lugs, making the trackunserviceable. Thus, a track belt having guide-drive lugs which arestronger and more resistant to wear is desired.

United States Patent Publication No. 2008/0136255 A1 discloses anendless track belt for use in an industrial or agricultural vehicle. Theendless rubber track belts described therein include a rubber carcasshaving an inner surface having one or more guide-drive lugs and an outersurface having tread lugs. The guide-drive lugs include reinforcementlayers that partially or substantially cover all or a portion of the endfaces of the guide-drive lugs. The reinforcement layers may includecontinuous strips, or discrete strips. The reinforcement layer may alsobe fabric cut outs to match the shape of the guide-drive end faces ofthe guide-drive lugs.

U.S. Pat. No. 6,974,196 B2 describes an endless track for an industrialor agricultural vehicle consisting of a body formed of a rubber materialhaving an outer surface displaying a series of ground engaging profileslongitudinally spaced along the surface and an inner surface displayinga series of longitudinally spaced guide-drive lugs adapted to be engagedby guide-drive sprockets on the vehicle driving assembly. The body ofthe endless track is fabric reinforced. One layer of fabriclongitudinally extends at a distance from the inner surface of the trackand has a width slightly less than the width of the guide-drive lugs sothat the fabric may extend inside the guide-drive lugs to increase theirrigidity.

U.S. Pat. No. 8,567,876 B2 discloses a concept for a fabric reinforcedrubber track guide-drive lug that provides a guide-drive lug whichincorporates a fabric on or close to the surface of the lug to providereinforcement. However, in some conditions, this surface reinforcementis often substantially abraded in service by contact with the wheels ofthe tracked vehicle and consequently does not last through the potentiallife of the track.

Thus, there is an ongoing need for endless tracks for industrial oragricultural vehicles with improved guide-drive lugs that extend theuseable life of the track in conditions where guide-drive lug wear ordamage are the primary life limiting conditions, such need met, at leastin part, with embodiments according to the following disclosure.

SUMMARY

This summary is provided to introduce a selection of concepts that arefurther described below in the detailed description. This summary is notintended to identify key or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in limiting the scope ofthe claimed subject matter.

In some embodiments of the disclosure, endless vehicle tracks include abody formed of an elastomeric material having an outer surfacedisplaying a series of ground engaging profiles longitudinally spacedalong the outer surface, and an inner surface formed a urethanereinforcement material. The inner surface generally displays a series oflongitudinally spaced guide-drive lugs for retaining the track on thevehicle and/or driving the vehicle. In some aspects, the urethanereinforcement defines the inner surface of the body, and the urethanereinforcement may even be a continuous structure forming a base of theinner surface. In some cases, the urethane reinforcement defines wheelpath regions of the body, and the urethane reinforcement may even formthe guide-drive lugs. In some embodiments, the endless vehicle trackfurther includes a fabric reinforcement layer disposed beneath or uponthe outer surface of the upper face of the guide-drive lugs.

In some aspects, the urethane reinforcement is formed from an admixturecomprising a castable urethane material. In some cases, the castableurethane material is a prepolymer containing methylene diphenyldiisocyanate (MDI), and in some aspects, the MDI is a methylene diphenyldiisocyanate terminated polycaprolactone prepolymer. In some otheraspects, the castable urethane material is a prepolymer containingtoluene diisocyanate (TDI), which may be a TDI terminatedpolycaprolactone prepolymer.

Some other embodiments of the disclosure are tracks including an outersurface formed of an elastomeric material displaying a series of groundengaging profiles, and a base disposed on the elastomeric material,where the base defines an inner surface and a series the guide-drivelugs. The base is generally formed of a urethane reinforcement material.The urethane reinforcement may be a continuous structure forming theinner surface, and may also form at least one wheel path region of thetrack. The urethane reinforcement may also form the guide-drive lugs.

Yet other embodiments of the disclosure are endless vehicle trackshaving an outer portion formed of an elastomeric material and displayinga series of ground engaging profiles, as well as an inner portion formedof a urethane reinforcement material and displaying a series theguide-drive lugs. The urethane reinforcement is formed from an admixturecomprising a castable urethane material selected from one of aprepolymer comprising methylene diphenyl diisocyanate (MDI), aprepolymer comprising toluene diisocyanate (TDI), and mixtures thereof.Either of the MDI and TDI may be an isocyanate terminatedpolycaprolactone prepolymer.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the disclosure will hereafter be described withreference to the accompanying drawings, wherein like reference numeralsdenote like elements. It should be understood, however, that theaccompanying figures illustrate the various implementations describedherein and are not meant to limit the scope of various technologiesdescribed herein, and:

FIG. 1 illustrates a track assembly which may be used on an industrialor agricultural vehicle, according to an embodiment of the disclosure;

FIG. 2 depicts, in a perspective view, a portion of a track whereguide-drive lugs both retain the track on the vehicle and are engagedand driven by a guide-drive wheel in accordance with an embodiment ofthe disclosure; and,

FIGS. 3 and 4 are fragmented cross-sectional views of the portion of atrack depicted in FIG. 2, in accordance with aspects of the disclosure.

DETAILED DESCRIPTION

The following description of the variations is merely illustrative innature and is in no way intended to limit the scope of the disclosure,its application, or uses. The description and examples are presentedherein solely for the purpose of illustrating the various embodiments ofthe disclosure and should not be construed as a limitation to the scopeand applicability of the disclosure. While the compositions of thepresent disclosure are described herein as comprising certain materials,it should be understood that the composition could optionally comprisetwo or more chemically different materials. In addition, the compositioncan also comprise some components other than the ones already cited. Inthe summary of the disclosure and this detailed description, eachnumerical value should be read once as modified by the term “about”(unless already expressly so modified), and then read again as not somodified unless otherwise indicated in context. Also, in the summary ofthe disclosure and this detailed description, it should be understoodthat a range or dimension listed or described as being useful, suitable,or the like, is intended that any and every value or dimension withinthe range, including the end points, is to be considered as having beenstated. For example, “a range of from 1 to 10” is to be read asindicating each and every possible number along the continuum betweenabout 1 and about 10. Thus, even if specific data points within therange, or even no data points within the range, are explicitlyidentified or refer to only a few specific, it is to be understood thatinventors appreciate and understand that any and all data points withinthe range are to be considered to have been specified, and thatinventors had possession of the entire range and all points within therange.

Unless expressly stated to the contrary, “or” refers to an inclusive orand not to an exclusive or. For example, a condition A or B is satisfiedby anyone of the following: A is true (or present) and B is false (ornot present), A is false (or not present) and B is true (or present),and both A and B are true (or present).

In addition, use of the “a” or “an” are employed to describe elementsand components of the embodiments herein. This is done merely forconvenience and to give a general sense of concepts according to thedisclosure. This description should be read to include one or at leastone and the singular also includes the plural unless otherwise stated.

The terminology and phraseology used herein is for descriptive purposesand should not be construed as limiting in scope. Language such as“including,” “comprising,” “having,” “containing,” or “involving,” andvariations thereof, is intended to be broad and encompass the subjectmatter listed thereafter, equivalents, and additional subject matter notrecited.

Also, as used herein any references to “one embodiment” or “anembodiment” means that a particular element, feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. The appearances of the phrase “in oneembodiment” in various places in the specification are not necessarilyreferring to the same embodiment.

Embodiments according to the disclosure, are tracks which generallyinclude a body having an outer surface displaying a series of groundengaging profiles longitudinally spaced along the outer surface andformed of an elastomeric material, and an inner surface formed of aurethane reinforcement material, such as a castable urethane material,where the inner surface includes a series of longitudinally spacedguide-drive lugs for retaining the track on the vehicle and/or drivingthe vehicle. The track embodiments according to the disclosure provideimproved transfer of torque and power through incorporation of urethanematerial in various areas of the track construction, and may be combinedwith other polymers and metal combinations to provide traction andrubber isolation. Further, longer track life may be realized as well.

As used in the summary and this detailed description, the phrase“elastomeric material” means a material comprising at least oneelastomer that can be reinforced with at least one filler such as carbonblack, which may be a natural rubber or synthetic rubber, such asemulsion styrene-butadiene rubber, solution styrene-butadiene rubber,synthetic polyisoprene rubber, polybutadiene rubber, or a blend ofnatural and synthetic rubbers. Such elastomeric materials may also bemixed with other materials, such silica, clay, organic fiber, inorganicmetal powder, mineral powder, talc, calcium sulfate, calcium silicate,distillates, curatives, accelerators, activators, processing aids,antioxidant packages, pigments, and the like.

The phrase “castable urethane material” means polyurethane formingmaterial(s) used in a method of casting where a mold is filled with aliquid synthetic polymer, which then hardens. In some embodimentsaccording to the disclosure, casting may be accomplished with the liquidpolymer plus an effective amount of a “hardener” liquid, whichfunctionally contains a second polymer or reactant, for use in forming afinal product which is a copolymer. Copolymers contain two differentalternating chemical entities in the final polymer molecule. Forexample, in a polyurethane casting process, the polyurethane polymerstructure may be formed by reacting a di- or polyisocyanate with apolyol or polyamine. Nonlimiting examples of such materials includeDURACAST® C930 MDI-terminated polycaprolactone prepolymer reacted withDURACURE™ C3-LF (4,4′-diaminodiphenylmethane), both available fromChemtura Corporation, Philadelphia, Pa.

The isocyanates and polyols or polyamines used to make polyurethanes mayin some aspects contain on average two or more functional groups permolecule. The materials are mixed, introduced into the mold, and exposedto certain conditions (i.e. temperature, time, pressure, etc.) to formthe polyurethane polymer structure or body. In some aspects, the castedurethane materials are prepared by a low pressure casting process wherepressure within an empty mold is sufficiently reduced, and low pressureis used to transfer the reaction components into the empty mold, whichthen react and cast the structure. In some other aspects, the structureare formed using a compression mold process which does not involvelowering pressure in the mold, but rather, high pressure is used totransfer the reaction components into the empty mold, and sufficientforces are placed on the components in the formation of the structure inthe mold. In yet other embodiments, the casturethane materials areprepared by pouring the reactants into a mold, and allowing thestructure to form under suitable conditions.

In some cases, the polyurethane structure is first cast by combining andreacting the polyisocyanate and polyol or polyamine components, and thenthe structure combined with the elastomeric material and otherreinforcement components to form a track. Sufficient heat and/orpressure may be provided to vulcanize or otherwise cure the track. Suchheat and/or pressure may also be suitable to promote sufficient bondingof the casted urethane structure, elastomeric material and reinforcementcomponents.

The castable urethane material(s) may also be mixed with variousadditives in conventional or suitable amounts known to persons havingordinary skill in the art. Such additives may include, and are notlimited to, cross-linking agents, accelerators, retardants to prevent anunduly quick cure, antioxidants, aging resistance aids (e.g., ozone andUV resistance), adhesion promoters, processing aids, flame retardancyadditives, reinforcing agents and fillers, such as carbon black, silica,other mineral fillers, lignin, fibers, friction modifiers such asultra-high molecular weight polyethylene (UHMWPE),polytetrafluoroethylene (PTFE), and the like. In some cases, carbonblack, silver salts, or any other suitable electrically conductivematerials may also be added to control and/or reduce static electricitybuildup. Reinforcing fillers are typically utilized at a level which iswithin the range of about 50 parts per hundred parts of resin (phr) toabout 150 phr.

Now referencing FIG. 1, which illustrates a track assembly 100 which maybe used on an industrial or agricultural vehicle (not shown). The trackassembly 100 includes a guide-drive wheel 102 having a plurality ofteeth or guide-drive bars 104 that are positioned for mating engagementwith guide-drive lugs 106. The guide-drive lugs 106 are mounted on arubber track 108 having an endless elongate carcass defining alongitudinal direction around the circumference thereof. The endlesstrack carcass has an outer surface 110 including a plurality of groundengaging tread lugs 114 and an inner surface 116 with a plurality ofguide-drive lugs 106, typically located on or near the center portion ofthe carcass.

FIG. 2 illustrates one embodiment according to the disclosure whereguide-drive lugs both retain the track on the vehicle and are engaged bythe guide-drive wheel to transfer power to the track. In anotherembodiment of the disclosure, the guide-drive lugs are only provided forthe purpose of retaining the track on the vehicle. In this scenario, theguide-drive lug only act in the capacity of guide-lugs. In cases wherethe lugs act to both guide and guide-drive the track, each guide-drivelug 106 comprises an elongated shaped bar with inclined guide-drivefaces 204, 206, and an upper flat face 208. The inclined faces aretypically known as the guide-drive face 204 and the reverse face 206 ofthe guide-drive lugs 106. End or guiding faces 210, 212 may be flat orin the alternative they can have various other suitable shapes, such astapered, convex, concave, and the like. Wheel path areas 216 aregenerally disposed adjacent the guide-drive lugs 106. In embodimentsaccording to the disclosure, guide-drive lugs 106 and wheel path areas216 adjacent thereto are components of the inner surface of the track,and formed of urethane reinforcement material. Outer surface 110displaying engaging tread lugs 114 are generally formed of theelastomeric material.

Embedded within the elastomeric material forming outer surface 110 areone or more reinforcement layers 218 which extend transversely along thetrack width. The reinforcement layers 218 may include such components aslongitudinal cable reinforcement layers, fabric reinforcement layers,transverse cable reinforcement layers (disposed at right angles to thelongitudinal direction) or any other reinforcement layer known to thoseskilled in the art.

Now referring to FIG. 3 which shows a cross view taken at referenceplane 8 in FIG. 2, guide-drive lugs 106 defining guide-drive faces 204,206, and upper flat face 208, as well as guide-drive body 214 are formedfrom urethane reinforcement material. In some embodiments, reinforcementlayer(s), such as a fabric, may be disposed within guide-drive body 214,adjacent the surface of guide-drive lugs 106. Urethane reinforcementmaterial also forms base 220 of the urethane reinforcement structure.Base 220 also defines wheel path areas of the track, as described infurther detail in FIG. 4.

With reference to FIG. 4, which depicts a cross-sectional view taken atreference plane 6 of the track shown in FIG. 2, guide-drive lug 106 andthe respective body 214, as well as base 220 are formed of urethanereinforcement material, such as castable urethane material. The innersurface of the track is defined by guide-drive lug 106 and region 402 ofthe track, which is a continuous urethane reinforcement materialsurface. Further, base 220 also defines wheel path areas 404 of innersurface 402 of the track.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. Example embodiments areprovided so that this disclosure will be sufficiently thorough, and willconvey the scope to those who are skilled in the art. Numerous specificdetails are set forth such as examples of specific components, devices,and methods, to provide a thorough understanding of embodiments of thedisclosure, but are not intended to be exhaustive or to limit thedisclosure. It will be appreciated that it is within the scope of thedisclosure that individual elements or features of a particularembodiment are generally not limited to that particular embodiment, but,where applicable, are interchangeable and can be used in a selectedembodiment, even if not specifically shown or described. The same mayalso be varied in many ways. Such variations are not to be regarded as adeparture from the disclosure, and all such modifications are intendedto be included within the scope of the disclosure.

Also, in some example embodiments, well-known processes, well-knowndevice structures, and well-known technologies are not described indetail. Further, it will be readily apparent to those of skill in theart that in the design, manufacture, and operation of apparatus toachieve that described in the disclosure, variations in apparatusdesign, construction, condition, erosion of components, gaps betweencomponents may present, for example.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner”, “adjacent”, “outer,”“beneath,” “below,” “lower,” “above,” “upper,” and the like, may be usedherein for ease of description to describe one element or feature'srelationship to another element(s) or feature(s) as illustrated in thefigures. Spatially relative terms may be intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the example term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

Although a few embodiments of the disclosure have been described indetail above, those of ordinary skill in the art will readily appreciatethat many modifications are possible without materially departing fromthe teachings of this disclosure. Accordingly, such modifications areintended to be included within the scope of this disclosure as definedin the claims.

What is claimed is:
 1. An endless vehicle track comprising a bodycomprising an elastomeric material forming an outer surface displaying aseries of ground engaging profiles longitudinally spaced along the outersurface, and an inner surface comprising a urethane reinforcement, theinner surface displaying a series of longitudinally spaced guide-drivelugs for retaining the track on the vehicle and/or driving the vehicle;wherein the urethane reinforcement is formed from an admixturecomprising a castable urethane material; and, wherein the castableurethane material consists of a liquid which completely fills a mold andhardens to form the urethane reinforcement.
 2. The endless vehicle trackof claim 1 wherein the urethane reinforcement defines the inner surfaceof the body.
 3. The endless vehicle track of claim 1 wherein theurethane reinforcement is a continuous structure comprising a base. 4.The endless vehicle track of claim 1 wherein the urethane reinforcementdefines wheel path regions of the body.
 5. The endless vehicle track ofclaim 1 wherein the urethane reinforcement forms the guide-drive lugs.6. The endless vehicle track of claim 1 further comprising a fabricreinforcement layer disposed in the urethane reinforcement proximate orupon upper faces of the guide-drive lugs.
 7. The endless vehicle trackof claim 1 wherein the castable urethane material is a prepolymercomprising methylene diphenyl diisocyanate (MDI).
 8. The endless vehicletrack of claim 1 wherein the castable urethane material comprises amethylene diphenyl diisocyanate (MDI) terminated polycaprolactoneprepolymer.
 9. The endless vehicle track of claim 1 wherein the castableurethane material is a prepolymer comprising toluene diisocyanate (TDI).10. The endless vehicle track of claim 9 wherein the castable urethanematerial comprises a toluene diisocyanate (TDI) terminatedpolycaprolactone prepolymer.
 11. A track comprising: an outer surfaceformed of an elastomeric material displaying a series of ground engagingprofiles; and, a base disposed on the elastomeric material, the basedefining an inner surface and a series the guide-drive lugs; wherein thebase comprises a urethane reinforcement; wherein the urethanereinforcement is formed from an admixture comprising a castable urethanematerial; and, wherein the castable urethane material consists of aliquid which completely fills a mold and hardens to form the urethanereinforcement.
 12. The track of claim 11 wherein the urethanereinforcement is a continuous structure forming the inner surface. 13.The track of claim 11 wherein the urethane reinforcement forms at leastone wheel path region of the track.
 14. The track of claim 11 whereinthe urethane reinforcement forms the guide-drive lugs.
 15. The track ofclaim 11 wherein the castable urethane material is a prepolymercomprising methylene diphenyl diisocyanate (MDI).
 16. The track of claim11 wherein the castable urethane material comprises a methylene diphenyldiisocyanate (MDI) terminated polycaprolactone prepolymer.
 17. The trackof claim 11 wherein the castable urethane material is a prepolymercomprising toluene diisocyanate (TDI).
 18. An endless vehicle trackcomprising: an outer portion formed of an elastomeric materialdisplaying a series of ground engaging profiles; and, an inner portioncomprising a urethane reinforcement and displaying a series theguide-drive lugs; wherein the urethane reinforcement is formed from anadmixture comprising a castable urethane material selected from one of aprepolymer comprising methylene diphenyl diisocyanate (MDI), aprepolymer comprising toluene diisocyanate (TDI), and mixtures thereof;and, wherein the castable urethane material consists of a liquid whichcompletely fills a mold and hardens to form the urethane reinforcement.19. The track of claim 18 wherein the castable urethane materialcomprises a methylene diphenyl diisocyanate (MDI) terminatedpolycaprolactone prepolymer.
 20. The track of claim 18 wherein thecastable urethane material comprises a toluene diisocyanate (TDI)terminated polycaprolactone prepolymer.